There's a good chance Recovery will not run from it's partition after upgrading to Windows 7 so if you want the bloated factory install you'd then need the Recovery Disks which you made when you set up Vista or order from HP: HP Recover Windows 7 Operating System Using HP Recovery - HP Customer Care (United States - English)
Then you'd need to run an inferior in-place Upgrade from Vista which is a lot of trouble to restore the worst load of factory bloatware in the industry.
However if you have a Windows 7 Upgrade DVD you can use it to Clean Reinstall - Factory OEM Windows 7
to get a superior install of just the OS without the sponsored crapware and useless HP utilities which have much better versions built into Windows 7. Everything you need is in the blue link.